CN112665519B

CN112665519B - Device and method for measuring radial deformation by laser

Info

Publication number: CN112665519B
Application number: CN202110075140.5A
Authority: CN
Inventors: 彭绍驰; 经来旺; 李树文
Original assignee: Anhui University of Science and Technology
Current assignee: Anhui University of Science and Technology
Priority date: 2021-01-20
Filing date: 2021-01-20
Publication date: 2022-08-02
Anticipated expiration: 2041-01-20
Also published as: CN112665519A

Abstract

A device and a method for measuring radial deformation by laser are used for measuring radial deformation in a single-axis experiment and can effectively solve the defects that the existing device for measuring radial deformation has large error and more influenced factors and cannot obtain radial deformation in real time. The device comprises a fixing plate 1, a clamping plate 2, a laser emitter 3, an outer reflection ring 4 and an inner reflection ring 5. The device is simple to install, and can accurately measure the radial deformation in real time.

Description

Device and method for measuring radial deformation by laser

Technical Field

The invention belongs to the technical field of geotechnical tests and relates to a device and a method for measuring radial deformation by using laser.

Background

In geotechnical tests, the measurement of the radial deformation of a test block to obtain the poisson's ratio is a prerequisite for other researches. At present, the main methods for measuring the radial deformation of the test block comprise a fixed local displacement sensor and a strain gauge method, and the methods have large measurement errors, are greatly influenced by the operation of experimenters, and cannot well measure the radial deformation under the condition of large deformation. With the popularization of dynamics research, the relationship between radial deformation and time needs to be explored urgently, so that it is very important to research a device and a method capable of measuring radial deformation accurately in real time.

Disclosure of Invention

In order to overcome the defects that the conventional device for measuring the radial deformation has large error and a plurality of influenced factors and cannot obtain the radial deformation in real time, the invention provides the device and the method for measuring the radial deformation by using the laser, which can accurately measure the radial deformation in real time.

The technical scheme adopted by the invention for solving the problems is as follows:

the utility model provides a device that laser survey radial deformation, can be accurate, real-time measurement radial deformation for radial deformation's measurement in the unipolar experiment, its device includes fixed plate 1, splint 2, laser emitter 3, outer reflective ring 4, internal reflection ring 5. The laser emitter 3 and the outer reflection ring 4 are fixed on the fixing plate 1 through the clamping plate 2.

A method for measuring radial deformation by laser comprises the following steps:

firstly, assembling a measuring device, sleeving the inner reflection ring 5 on the test block 7, and adjusting the height of the fixed plate 1 to enable the outer reflection ring 4 and the inner reflection ring 5 to be approximately at the same horizontal height.

In the second step, the distance d between the inner reflective ring 5 and the outer reflective ring 4 and the radius R of the test block are measured.

Thirdly, the laser emitter 3 is opened, light spots with equal intervals appear on the outer reflection ring 4, and a point N far away from the laser emitter 3 is selected ₁ The position thereof and the number of spots N between the spot and the laser emitter 3 are recorded.

Fourthly, calculating to obtain an included angle phi, an arc length S and an included angle N between two adjacent light points on the outer reflection ring 4 and the circle center of the test block through a known laser incident angle theta (which is very small) ₁ Total arc length S of point ₁ . The calculation formula is as follows:

S ₁ ＝NS

fifthly, carrying out a single-axis experiment, continuously moving the light spot on the outer reflection ring along with the experiment, and recording N ₁ The distance Δ S over which the dot moves.

Sixthly, calculating the included angle between two adjacent light points on the deformed outer reflection ring 4 and the circle center of the test block

Arc length

And to new N ₁ Total arc length S of point ₂ . The calculation formula is as follows:

seventh step of measuring N ₁ The distance Δ S over which the point moves calculates the radial deformation Δ R. The calculation formula is as follows:

the invention has the beneficial effects that: the assembly is simple, and the influence of the operation of an experimenter is small; the radial deformation of the test block can be accurately measured in real time.

Drawings

The invention is further illustrated with reference to the following figures and examples:

FIG. 1 is a schematic diagram of the present invention;

FIG. 2 is a schematic diagram of the derivation of the non-distorted equations of the present invention;

FIG. 3 is a schematic diagram of the post-deformation formula derivation of the present invention;

fig. 4 is a diagram of a three-dimensional device of the present invention.

In the figure, 1, a fixing plate, 2, a clamping plate, 3, a laser emitter, 4, an outer reflection ring, 5, an inner reflection ring, 6, a light ray and 7, a test block are arranged.

Detailed Description

In fig. 1, a laser transmitter 3 and an outer reflection ring 4 are fixed on a fixing plate 1 through a clamping plate 2, the laser transmitter 3 transmits laser at a small incident angle, the laser is reflected on an inner reflection ring 5 and the outer reflection ring 4 for multiple times, a plurality of photoelectricity (the arc length between two light spots is equal) is formed on two reflection plates, and a plurality of light rays 6 are formed between the two plates.

In fig. 1, the spot position of the reflected light ray 6 on the outer reflector changes due to the change of the radius of the inner reflector 5, which results in the change of the reflection angle. The radius of the inner reflection ring 5 becomes larger and the reflection angle becomes smaller. The arc length between two adjacent spots decreases.

In fig. 4, the inner reflection ring 5 is sleeved on the test block 7, and during the uniaxial experiment, the radial deformation of the test block 7 drives the radial deformation of the inner reflection ring 5.

Claims

1. A method for measuring radial deformation by laser uses a device for measuring radial deformation by laser, the device comprises a fixing plate (1), a clamping plate (2), a laser emitter (3), an outer reflection ring (4) and an inner reflection ring (5), the laser emitter (3) is arranged on the outer reflection ring (4), and the outer reflection ring (4) is fixed on the fixing plate (1) through the clamping plate (2);

the method comprises the following steps:

firstly, assembling a measuring device, sleeving an inner reflection ring (5) on a test block (7), and adjusting the height of a fixed plate (1) to enable an outer reflection ring (4) and the inner reflection ring (5) to be approximately at the same horizontal height;

secondly, measuring the distance d between the inner reflection ring (5) and the outer reflection ring (4) and the radius R of the test block;

thirdly, turning on the laser emitter (3), enabling light spots with equal intervals to appear on the outer reflection ring (4), and selecting a point N far away from the laser emitter (3) ₁ Recording the position and the number N of light spots between the point and the laser emitter (3);

fourthly, calculating to obtain the included angle phi, the arc length S and the included angle N between two adjacent light points on the outer reflection ring (4) and the circle center of the test block through the known laser incident angle theta ₁ Total arc length S of point ₁ (ii) a The calculation formula is as follows:

S ₁ ＝NS；

fifthly, carrying out a single-axis experiment, continuously moving the light spot on the outer reflection ring along with the experiment, and recording N ₁ The distance Δ S by which the point moves;

sixthly, calculating the included angle between two adjacent light points on the deformed outer reflection ring (4) and the circle center of the test block

Arc length

And to new N ₁ Total arc length S of point ₂ The calculation formula is as follows:

seventh step of measuring N ₁ Calculating radial deformation delta R according to the moving distance delta S of the point; the calculation formula is as follows: